The Petroleum system

This publication in 17 individually authored summaries by U.S. Geological Survey scientists presents a revised and expanded list of the petroleum systems within the United States and summarizes the status of research for a number of petroleum- related topics and investigative methods. The revised and expanded list now includes 130 petroleums systems within the United States, 25 of which are classified as known systems. In a brief description of the usefulness of the stratigraphic cross section, Molenaar shows how this type of graphic illustration depicts important vertical and lateral lithostratigraphic relations. Two summaries on ancient and modem deep- water sediments are included. The carbonate slope apron and base-of-slope apron are compared and contrasted by Cook and Mullins. Summarizing the work of many investigators, Normark indicates how siliciclastic fan models based on field mapping, submarine acoustic imaging, and subsurface seismic stratigraphy compare and contrast. Investigations about porosity in petroleum reservoir rocks are discussed by Schmoker and Gautier. Pollastro discusses the uses of clay minerals as exploration tools that help to elucidate basin, source-rock, and reservoir history. The status of fission-track analysis, which is useful for determining the thermal and depositional history of deeply buried sedimentary rocks, is outlined by Naeser. The various ways workers have attempted to determine accurate ancient and present-day subsurface temperatures are summarized with numerous references by Barker. Clayton covers three topics: (1) the role of kinetic modeling in petroleum exploration, (2) biological markers as an indicator of depositional environment of source rocks and composition of crude oils, and (3) geochemistry of sulfur in source rocks and petroleum. Anders and Hite evaluate the current status of evaporite deposits as a source for crude oil. The current knowledge on the effect of biodegradation on crude oils is covered by Michael. Research on the origin and recovery of heavy oil and natural bitumen is discussed by Meyer. Two contributions ~on gaseous hydrocarbons are included: Kvenvolden discusses the latest thinking on the origin of methane and nitrogen, redefines the terms associated with the origin of methane, and suggests possible implications these ideas have on exploration strategy; and Collett and Kvenvolden review investigations of marine and continental natural gas hydrate occurrences. Crovelli reviews quantitative aspects of petroleum resource assessment methodolo- gies. Lastly, publications written by personnel of the USGS Branch of Petroleum Geology and published during 1988 are listed in a separate bibliography.